im wondering about the sequence of events here. it could be that the installation electrician expect the DNO to provide a tnc-s supply hence the earth block? the installer has provided rcbo protection on the final circuits but not sub main distribution which would be compliant with selectivity of protective devices IF a tnc-s system had been installed by the DNO. however the installation should not have been energised due to the fact that an EIC could not have been produced with readings that complied with bs 7671 until the dno provided the new tnc-s supply. i would certainly be contacting them and researching the history of this installation
The way that earth is just lashed across the building is diabolical too. Even if an incoming 100ma RCD were fitted, someone looking for an easy bit of scrap would have that away in seconds. I would love someone to make a vid explaining how supplys in the street generally work and how the pme is or is not decided to be the way to go.......
Anyone looking for scrap for basic understanding of electricity would cut out earth wires because it doesn’t pose an immediate risk compared to cutting a live conductor
So what are the mcb zs values for tt system Dose the zs of a circuit just need to be under 1667 to pass so if it's a 32 amp ring or a 6 amp lights or 20 amp radial as long as its under 1667 is that fine Any help would be great thanks
Well spotted mate! 👍. I would've missed that but that's purely down to a lack of testing experience. I would contact the DNO anyway to be 100% sure as the installer may have just forgotten to put a sticker on?
That’s a sub distribution board. This means is feeding some consumer units who are RCD protected. If I was you first thing I was spotted was the breakers are the other way around fitted...
im wondering about the sequence of events here. it could be that the installation electrician expect the DNO to provide a tnc-s supply hence the earth block? the installer has provided rcbo protection on the final circuits but not sub main distribution which would be compliant with selectivity of protective devices IF a tnc-s system had been installed by the DNO.
however the installation should not have been energised due to the fact that an EIC could not have been produced with readings that complied with bs 7671 until the dno provided the new tnc-s supply. i would certainly be contacting them and researching the history of this installation
The way that earth is just lashed across the building is diabolical too. Even if an incoming 100ma RCD were fitted, someone looking for an easy bit of scrap would have that away in seconds. I would love someone to make a vid explaining how supplys in the street generally work and how the pme is or is not decided to be the way to go.......
Anyone looking for scrap for basic understanding of electricity would cut out earth wires because it doesn’t pose an immediate risk compared to cutting a live conductor
@@UKsystems exactly. Seems quite odd noone ever picked up on this when installing things beyond that distribution board.
Could the DNO not be slightly at fault also for dobbing those tails in to that supply?
So what are the mcb zs values for tt system
Dose the zs of a circuit just need to be under 1667 to pass so if it's a 32 amp ring or a 6 amp lights or 20 amp radial as long as its under 1667 is that fine
Any help would be great thanks
Well spotted mate! 👍. I would've missed that but that's purely down to a lack of testing experience.
I would contact the DNO anyway to be 100% sure as the installer may have just forgotten to put a sticker on?
That very much sounded like Craig Gifford?
That’s a sub distribution board. This means is feeding some consumer units who are RCD protected. If I was you first thing I was spotted was the breakers are the other way around fitted...
It really isn't difficult to understand TT earthing systems and the correct use of RCD protection!
Hi, really enjoying all the useful info from your vids, can you tell what the outcome was regarding the lack of 100mA RCD. Thanks
Hi and thanks for the feedback. This failed the inspection, last I saw of it.
probably got an ok from another "electrician". have you ever visually checked what they done after?
Gary Davies. whay do you sugest 100 mA rcd instead of the 30 mA one?
Gary Davies why 100ma and not 30?
@@LSF315 Discrimination...
What was your measured Ze values ?
a quite decent 1.56Ω, but the new intake was quite local.
the RCD is next to panel external RCD
EDI Bab those RCD units are submains to another panel, they don't feed the distribution board I highlight.
Can't really see but it looks like N-E